Simple Pivot Table Years (number format) in Filter shows as Accounting Format

[treym]

Hello. This is a weird event in my pivot table. I have a raw/flat file that has a column with years in it formatted as a number (2015, 2016, etc). In my pivot table filters and if used as column headers or values they show as accounting formatted ($2,017). I've done everything from formatting, etc. but they still show in accounting form. Any ideas how this happened and how to correct? Thanks.